The disease Alzheimer It is a progressive neurodegenerative disorder that occurs due to the progressive loss of neurons.
It is the most common cause of dementia in older people, and along with other neurodegenerative dementias, Alzheimer’s disease is a major cause of disability and will have exponential growth in the coming decades, with an estimated 150 million people affected by 2050. .
One of the causes of this neurological disease is age, but it is not the only one.
- “It is a pathology of multifactorial origin, conditioned by genetic and/or environmental factors, which are also influenced by others such as high blood pressure, hypercholesterolemiaobesity, sedentary lifestyle, smoking or diabetes” explain from the Spanish Society of Neurology (SEN).
And as with all diseases, early detection allows improving the prognosis and quality of life of patients.
In this sense, a recent Spanish study has determined that Alzheimer’s can be diagnosed through routine analysis, even in people with very early symptoms.
It involves detecting a protein in the blood, the phosphorylated tau protein, which determines the presence of the disease.
Biomarkers for Alzheimer’s disease
Currently, the diagnostic methods available, such as analyzing biomarkers in cerebrospinal fluid or performing brain neuroimaging tests, are very reliable, but they are expensive and relatively invasive, which limits their widespread use.
But if we want to be able to carry out early intervention, it is necessary to have an exact diagnosis. As explained Raquel Sánchez-Vallehead of the SNeurology service of the Clinic and the Alzheimer’s Unitas well as the research group of IDIBAPS.
- “Having specific markers that are easily accessible, such as blood biomarkers, would help offer an early diagnosis to a greater proportion of patients,”
And to date, different markers have been found, but they have only been tested in very specific groups of patients, so there is a lack of data in routine clinical practice cohorts to be able to implement their systematic use as diagnostic tools.
Therefore, the objective of the study was to determine the diagnostic capacity of five blood biomarkers (p-tau181, t-tau, NfL, GFAP and UCH-L1).
The ptau181 protein in the blood is related to the presence of Alzheimer’s disease, even in patients with few symptoms. / FREEPIK
A protein in the blood can diagnose Alzheimer’s disease
Between June 2019 and June 2021, 349 people consecutively treated in the Alzheimer’s and other cognitive disorders Unit at the Clínic Barcelona hospital were included.
From all of them, apart from the standard diagnostic procedure (cognitive and neuroimaging tests, neuropsychological examination, determination of markers in cerebrospinal fluid or through a PET scan), a blood sample was taken to determine the five plasma markers of cognitive impairment. under study, including phosphorylated tau protein (ptau181) and neurofilaments (NfL).
The results of this study demonstrate that the plasma protein ptau181 correlates with the presence of Alzheimer’s disease, even in patients with few symptoms.
- “This biomarker was able to distinguish between people with Alzheimer’s and people with non-neurodegenerative cognitive problems,” explains the Dr. Jordi Sarto, neurologist and researcher on the same team.
This means that the detection of ptau181 protein in the blood could have prevented more than half of the confirmatory diagnostic tests. “The idea is not to replace biomarkers in cerebrospinal fluid or the detection of amyloid plaques using PET, but, based on these results, to reduce these tests based on ptau181 levels,” says Albert Lladó Albert Lladó, neurologist at the Alzheimer’s and other cognitive disorders unit at the Hospital Clínic Barcelona and researcher at IDIBAPS.
On the other hand, the combination of plasma ptau181 and neurofilaments (NfL) was correlated with a diagnosis of frontotemporal dementia, another type of neurodegenerative disease.
- “These results suggest that these tests have adequate diagnostic performance to be implemented at the level of health care units.” dementia hospitalizations to increase the certainty of a clinical diagnosis and save more expensive tests (brain PET) or invasive tests (lumbar puncture) in many people,” says neurologist Mircea Balasa.
“For systematic clinical use, the next step would be to obtain approval from the regulatory authorities for the financing of these tests through the public health system,” the authors conclude.
